Overflow per segment

Abstract

Per-segment overflow ranges. One method includes acts for handling overflows of a mark stack. A reference to an object is accessed. The object is processed by attempting to place references to other objects referenced in the object onto a mark stack. An overflow condition of the mark stack is detected. A range in a segment is defined which includes the object that caused the overflow condition. The range is assigned on a per segment basis such that the range is defined to only include addresses in a single segment.

Description

BACKGROUNDBackground and Relevant Art[0001]In computer systems, there is often a need to manage memory. In particular, when objects are no longer used, it is useful to recover memory that was allocated for use with the objects. Some systems in use today use explicit memory management whereby the systems use a command to allocate memory and a corresponding command to free memory. For example, the C programming language includes a command “malloc” that can be used to allocate memory for an object and a command “free” that can be used to free memory that has been previously allocated. However, this type of memory allocation and de-allocation suffers from a number of drawbacks. In particular, free memory may be scattered throughout a memory structure. Additionally, this type of allocation and de-allocation allows for malicious attacks that can be used to compromise data. For example, a hacker can cause memory that has been allocated by one thread to be de-allocated such that a malicious...

AI Technical Summary

Benefits of technology

[0010]One embodiment described herein includes a method that may be practiced in a computing environment. The computing environment including application code that implements garbage collection functionality. The garbage collection functionality includes pushing object references onto a mark stack. Objects referenced on the mark stack can be marked so as to prevent memory for the objects from being recycled for use with other object instances. The method includes acts for handling overflows of a mark stack. A reference to an object is accessed. The object is processed by attempting to place references to other objects referenced in the object onto a mark stack. An overflow condition of the mark stack is detected. A range in a segment is defined which includes the object that caused the overflow condition. The range is assigned on a per segment basis such that the range is defined to only include addresses in a single segment.

Problems solved by technology

However, this type of memory allocation and de-allocation suffers from a number of drawbacks.

Additionally, this type of allocation and de-allocation allows for malicious attacks that can be used to compromise data.

When the mark stack is limited in size, the mark stack may overflow.

While it may not be necessary to examine the entire object heap as a range of the object heap that includes overflows can be implemented, as can be appreciated, this can nonetheless result in a time consuming and resource intensive marking process.

Linearly processing these segments can be a waste of system resources.

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